Hello Gardeners, I’m Amanda McNulty with Clemson Extension and Making It Grow. There is a host of letters following descriptions of vegetable plants when you look at seed catalogs and often these letters appear on the labels accompanying transplants for sale in garden centers. The land grant universities work closely with seed companies to come up with plants that can resist the many diseases and pests that destroy crops. When you look at tomato plants, these are some of the letters you see and the resistance they indicate. V – verticillium wilt, F, FF, or FFF means resistance to difference races of fusarium wilt. T is for tobacco mosaic virus. These are particularly valuable traits as these disease lasts for years and years and years in infected fields. The newest alphabet combo is TSWV – resistance to tomato spotted wilt virus, but resistance isn’t immunity -even these plants can succumb in years with high disease pressure.